因项目缘故需又一次定制SwitchButton,效果例如以下：

步骤例如以下：

1.圆角矩形的绘制

2.字体绘制

3.小圆绘制

4.左右滑动动画效果绘制

代码例如以下：

package com.smart.view;

import java.util.Timer;

import java.util.TimerTask;

import android.annotation.SuppressLint;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Paint.FontMetrics;

import android.graphics.Rect;

import android.graphics.RectF;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

public class MySwitchButton extends View{

	private int w, h;//组件宽高

	private boolean flag_switch;//开关标志

	private boolean flag_touch;//触摸标志

	private String ON = "ON";

	private String OFF = "OFF";

	private float textSize = 40;//字体大小

	private int color1 = 0xff999999;//关背景颜色

	private int color2 = 0xff3e9edb;//开背景颜色

	private int color_bg = color1;

	private int circle_bg_nomal = Color.WHITE;//圆正常情况下的背景

	private int circle_bg_touch = Color.YELLOW;//触摸时圆的背景

	//圆心

	private float y;

	private float x;

	private float radius;//圆半径

	private int distance = 10;//左右边距

	private OnCircleClickListner mOnCircleClickListner;

	public MySwitchButton(Context context) {

		super(context);

		System.out.println("---MySwitchButton1---");

	}

	public MySwitchButton(Context context, AttributeSet attrs, int defStyleAttr) {

		super(context, attrs, defStyleAttr);

		System.out.println("---MySwitchButton2---");

	}

	public MySwitchButton(Context context, AttributeSet attrs) {

		super(context, attrs);

		System.out.println("---MySwitchButton3---");

	}

	public void setOnCircleClickListner(OnCircleClickListner mOnCircleClickListner){

		this.mOnCircleClickListner = mOnCircleClickListner;

	}

	public boolean isFlag_switch() {

		return flag_switch;

	}

	public void setChecked(boolean flag_switch) {

		this.flag_switch = flag_switch;

		if(flag_switch){

			x = distance+radius;

			color_bg = color2;

		}else{

			x = w-(distance+radius);

			color_bg = color1;

		}

		circleMove();

//		invalidate();

	}

	@Override

	public boolean onTouchEvent(MotionEvent event) {

//		float x = event.getX();

//		float y = event.getY();

		switch (event.getAction()) {

		case MotionEvent.ACTION_DOWN:

			flag_touch = true;

			invalidate();

			break;

		case MotionEvent.ACTION_MOVE:

			break;

		case MotionEvent.ACTION_UP:

			if(mOnCircleClickListner!=null){

				mOnCircleClickListner.onClick(MySwitchButton.this,!flag_switch);

			}

			flag_touch = false;

			invalidate();

			break;

		}

		return true;

	}

	@Override

	protected void onSizeChanged(int w, int h, int oldw, int oldh) {

		super.onSizeChanged(w, h, oldw, oldh);

		this.w = w;

		this.h = h;

		y = h/2;

		radius =  h/2-distance;

		x = distance+radius;

//		color_bg = color1;

		circleMove();

//		invalidate();

		System.out.println("-----onSizeChanged----");

//		System.out.println("x:"+x);

//		System.out.println("w:"+w);

//		System.out.println("h:"+h);

	}

	@Override

	protected void onDraw(Canvas canvas) {

		System.out.println("-----onDraw----");

		Paint paint = new Paint();

		paint.setAntiAlias(true);

		canvas2RoundRect(canvas,paint);//圆角矩形

		canvas2Text(canvas,paint);//字体

		canvas2Circle(canvas,paint);//小圆

		super.onDraw(canvas);

	}

	public void canvas2RoundRect(Canvas canvas,Paint paint){

		paint.setColor(color_bg);

		RectF oval3 = new RectF(0, 0, w, h);

        canvas.drawRoundRect(oval3, 45, 45, paint);

	}

	public void canvas2Circle(Canvas canvas,Paint paint){

		if(flag_touch){

			paint.setColor(circle_bg_touch);

		}else{

			paint.setColor(circle_bg_nomal);

		}

//		circleMove();

//		System.out.println("drawX:"+x);

		canvas.drawCircle(x, y, radius, paint);

	}

	Timer timer;

	TimerTask task;

	public void circleMove(){//小圆运动轨迹

		final float startX =distance+radius;

		final float endX = w-(distance+radius);

		final long upDataDistance = 10;

		if(timer!=null){

			task.cancel();

			timer.cancel();

			timer=null;

			task=null;

		}

		timer = new Timer();

		task = new TimerTask() {

			@Override

			public void run() {

				if(flag_switch){

					x+=upDataDistance;//打开

				}else{

					x-=upDataDistance;//关闭

				}

				if(x>=endX){

					x=endX;

					this.cancel();

					timer.cancel();

					timer =null;

				}else if(x<startX){

					x = startX;

					this.cancel();

					timer.cancel();

					timer =null;

				}

				postInvalidate();

			}

		};

		timer.schedule(task, 8, 8);

	}

	public void canvas2Text(Canvas canvas,Paint paint){

		paint.setTextSize(textSize);

		paint.setColor(Color.WHITE);

		Rect rect = new Rect();

		if(flag_switch){

			paint.getTextBounds(ON, 0, ON.length()-1, rect);

			int textHight = rect.height();

			float textWight = paint.measureText(ON);

			canvas.drawText(ON, (w/2-textWight)/2, (h+textHight)/2, paint);

		}else{

			paint.getTextBounds(OFF, 0, OFF.length()-1, rect);

			float textWight = paint.measureText(OFF);

			int textHight = rect.height();

			canvas.drawText(OFF, w/2+(w/2-textWight)/2, (h+textHight)/2, paint);

		}

	}

	public interface OnCircleClickListner{

		public void onClick(View v,boolean flag);

	}

}

   <com.example.test_myview.MySwitchButton

        android:id="@+id/msb"

        android:layout_width="70dp"

        android:layout_height="27dp"

        />

监听接口时要调用public void setChecked(boolean flag_switch)该方法才干使小球左右滑动